John j



UNITED STATES PATENT OFFICE.

JOHN J. OBRIEN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE JOHN OBRIEN BOILER WORKS COMPANY, OF SAME PLACE.

. MANHOLE-COVER.

SPECIFICATION forming part of Letters Patent No. 595,647, dated December 14, 1897. 'nppiimon med .my 19,1897. serial No. 645,100. (No model.)

To all whom it may concern:

Be it known that I, JOHN J. OBRIEN, a citizen of the United States, residing at the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Covers for Boiler Manholes, Hand-Holes, dac., of which the followingis a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.

My invention relates to an improved form of cover for manholes, hand-holes, cleaningholes, and orhe'r like holes of a boiler.

My invention consists in features of novelty hereinafter fully described, and pointed out in the claims.

Figure I is a front view of my improved cover, the spider being removed. Fig. II is" IV. Fig. IV is a section taken on line IV IV, I

Fig. III, or on the same line, Fig. I. Fig. V is a sectional view illustrating the manner in which the bolt is introduced. Fig. VI is a face view representing an old form of cover on which my invention is an improvement. Fig. VII is a sectional view of the same, taken on line VII VII, Fig. VI.

Referring tothe drawings, I represents part of the outer wall of a boiler in whichis formed a man, hand, or other hole 2, closed, as usual, by a cover 3.

4 represents the ordinary spider, and 5 the ordinary bolt which is connected to the cover and which passes through the spider for holding the-cover in place. It has been customary to form in the cover a rabbeted recess or socket 7 to receive the head of the bolt 5, so that the bolt can be slipped into position after the cover has been placed in position. In order to introduce the bolt-head, it has been customary to cast the cover with that portion of the head of the cover that is indicated by A in Fig.v I omitted, thus leaving the cover with an opening in the semicircular form shown in Figs. VI and VII. This manner of forming the cover left it in a weakened condition, especially that part that was of reduced size. Furthermore, this manner of casting the cover left it so that the bolt would readily drop out of its socket before being tightened when the cover was placed with the socket open end down.

4In carrying out my invention I form the head of the cover as shown in the drawings and make an opening 6 from the bolt-headreceiving socket 7 to the `outer face of the head of the cover of less width in one direction than the head of the bolt, so that the head of the bolt has to be inserted edge first, so as to permit the head of the bolt to pass in, as shown clearly in Figs. IV and V.

The inner face of the opening 6 is rounded off, as shown at 8, to permit of the bolt-head being introduced into its socket 7 and its outer edge to pass into the opening, as shown in Fig. V. The opening 6 is large enough to receive the head of the bolt, as shown in Fig. I, and by placing the bolt with its shank opposite the slot 9 of the socket and with the head so that 'it will enter the opening 6 edge Iirst it is readily introduced by being moved from the position shown in full lines, Fig. V, to the position shown in dotted lines.

By thus forming the cover it is free from the objections stated, while its cost of production is not materially changed.

l0 represents the gasket placed between the flange of the cover and the boiler.

I claim as my inventionM 1. A cover for the manholes, hand-holes, dto., of boilers having a socket to receive the head of the retaining-bolt, and having an opening of less width in onedirection than the head of the bolt and extending from the outer face of the cover to the socket through which the head of the bolt is introduced edge first, substantially as set forth. v

2. In a cover for the manholes, hand-holes, dac., of boilers having a socket to receive the head of the retaining-bolt, and an opening 6 of less width in one direction than the head of the bolt and extending from the outer face of the cover to the socket and through which the head of the bolt is introduced edge rst, the inner wall of the hole being rounded as shown at 8 to permit the head'to turn into the socket and its outer edge to pass through the opening, substantially as set forth,

JOHN J. OBRIEN.

In presence of- E. S. KNIGHT, STANLEY SToNER. 

